This invention relates to a self-processing film unit for an instant camera, and more particularly to a peel-off self-processing film unit in which an image recording sheet with a positive image appearing therein is peeled off after completion of self-processing.
There is a film unit in which an image-recording sheet with a positive image formed therein is peeled off a self-processing film unit (hereinafter simply referred to as the "film unit"), so that it can be attached to a photo album, etc. There are two known types of this film unit. One type is a peel-apart type which has heretofore been widely used, and the other type is a peelable monosheet type. The first-mentioned peel-apart type film unit, as described in detail for example in Japanese Unexam. Patent Publ. No. Sho 61-48839, is characterized in that after an image is recorded in a photosensitive sheet, the photosensitive sheet is superimposed on an image-receiving sheet, then processing solution is spread between the photosensitive sheet and the image-receiving sheet, and after a predetermined processing time has passed, the image-receiving sheet with a positive image formed therein is peeled off as an image recording sheet. On the other hand, the second-mentioned peelable monosheet type film unit, as described for example in U.S. patent application Ser. No. 07/269,016 filed Nov. 9, 1988, comprises a photosensitive sheet formed of a single base sheet, an image-receiving layer coated on the base sheet, a peelable interlayer coated on the image-receiving layer and a photosensitive layer coated on the peelable interlayer, a processing solution container, a mask sheet, and a cover sheet all integrally formed into a single assembly. After processing, an image recording sheet integrally formed of the image-receiving layer and the base sheet is peeled off from the peelable interlayer.
However, in the peel-apart type, when the image-receiving sheet is peeled off, colored processing solution sticks to the photosensitive sheet. This processing solution has a certain viscosity. If it sticks to the user's hands, clothes, etc., it can dirty them. Moreover, as it is alkaline, it can damage clothing, etc. which it contacts. Therefore, the user is required to handle the film unit carefully after the image-receiving sheet is peeled off. Also, some users are disconcerted by the color of the processing solution.
On the other hand, in the peelable monosheet type, the lower surface of the peelable interlayer serves as the peelable surface. This peelable surface has viscosity. Besides, a blue photosensitive layer can be seen through the peelable interlayer. Therefore, this type again has the same problems as the peel-apart type.